The present invention concerns sheathing for packaging a predetermined volume of a biological substance intended to be immersed in a liquid cryogenic agent.
Sheathings are known formed of a thin tube in which is stored a liquid substance to be preserved, in particular for sample preservation, for example by the “vitrification” method, which consists in cooling the substance to be preserved quasi-instantaneously by immersing the sheathing and the biological substance that it contains in a liquid cryogenic agent (for example liquid nitrogen).
Once the biological liquid substance has been introduced into the thin tube, the sheathing is sealed at both ends by heat welding to seal it for subsequent immersion in the liquid nitrogen.